Orthopedic fixation devices and methods of installation thereof

ABSTRACT

The present invention is generally directed to orthopedic fixation devices that comprise a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element. The orthopedic fixation devices described herein can include modular locking clamp assemblies that can be fixed onto fasteners that are already implanted in bone. The modular locking clamp assemblies can include polyaxial locking clamp assemblies, as well as monoaxial locking clamp assemblies.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a continuation application of U.S. Ser. No.15/645,006, filed on Jul. 10, 2017 (published as U.S. Pat. Pub. No.2017-0303971), which is a continuation application of U.S. Ser. No.15/149,517, filed May 9, 2016, now issued as U.S. Pat. No. 9,730,735,which is a continuation application of U.S. Ser. No. 13/731,374, filedDec. 31, 2012, now issued as U.S. Pat. No. 9,358,047, which is acontinuation-in-part application of U.S. patent application Ser. No.13/183,965, filed on Jul. 15, 2011, now issued as U.S. Pat. No.8,888,827, which are each herein incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to orthopedic fixation devices, and, inone or more embodiments, to an orthopedic fixation device configured forloading of the bone fastener from the bottom of the tulip element.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. Often, these irregularities are treated byimmobilizing a portion of the spine. This treatment typically involvesaffixing a plurality of fixation devices to one or more vertebrae andconnecting the devices to an elongate rod that generally extends in thedirection of the axis of the spine.

Treatment for these spinal irregularities often involves using a systemof fixation devices to attain stability between spinal segments.Instability in the spine can create stress and strain on neurologicalelements, such as the spinal cord and nerve roots. In order to correctthis, implants of certain stiffness can be implanted to restore thecorrect alignment and portion of the vertebral bodies. In many cases, afixation device along with a vertical solid member can help restorespinal elements to a pain free situation, or at least may help reducepain or prevent further injury to the spine.

Typically, fixation devices may include a bone fastener (e.g., bonescrew, hook, etc.) for coupling the fixation device to vertebra.Fixation devices further may include a tulip element for coupling thebone fastener to the elongated rod. Clamp and/or wedge elements may beused to secure the bone fastener in the tulip element. A locking cap maybe used to secure the rod in the tulip element. While these designs canbe used in the treatment of spinal irregularities, they typicallyrequire loading of the bone fastener from the top of the tulip element.One drawback to this top-loading design is that different sizes of thetulip element must be used based on the diameter of the bone fastener toaccommodate passage of the fastener through the tulip element, as theinner bore of the tulip element will generally need to be larger thaneither the combined size of the bone fastener head and clamp element orthe bone fastener diameter. Another drawback to this top-loading designis that bone hooks cannot be used as they will generally not passthrough the tulip element. Yet another drawback to this top-loadingdesign is that bone fastener must be installed in the bone whileattached to the tulip element.

Accordingly, there exists a need for new and improved orthopedicfixation devices.

SUMMARY OF THE INVENTION

In an exemplary embodiment, the present invention provides an orthopedicfixation device. The orthopedic fixation device may comprise a couplingelement, the coupling element may comprise a bore there through and aninterior surface disposed about the bore. The orthopedic fixation devicefurther may comprise a bone fastener, wherein the bone fastenercomprises a head and an extension that extends from the head, whereinthe head is configured for loading into the coupling element through thebottom of the bore. The orthopedic fixation device further may comprisea locking clamp assembly. The locking clamp assembly may comprise aclamp element, wherein the clamp element comprises a first clamp portionand a second clamp portion, wherein the first and second clamp portionseach have an outer surface and an inner surface, wherein at least aportion of the outer surface is configured to engage the interiorsurface of the coupling element, and wherein at least a portion of theinner surface is configured to engage the head of the bone fastener. Thelocking clamp assembly further may comprise a wedge element, wherein thewedge element comprises a wedge bore configured to receive an upperportion of the clamp element and an inner wedge surface disposed aroundat least a lower portion of the wedge bore, wherein the inner wedgesurface is configured to engage at least portion of the outer surface ofthe first and second clamp portions.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred or exemplary embodiments of the invention, areintended for purposes of illustration only and are not intended to limitthe scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an exploded view of an orthopedic fixation device inaccordance with embodiments of the present invention;

FIG. 2 is a perspective view of a locking clamp assembly in accordancewith embodiments of the present invention;

FIG. 3 is a cross-sectional view of a locking clamp assembly inaccordance with embodiments of the present invention;

FIG. 4 is a top view of a wedge element in accordance with embodimentsof the present invention;

FIG. 5 is a side view of a wedge element in accordance with embodimentsof the present invention;

FIG. 6 is a cross-sectional view of a locking clamp assembly disposed ina tulip element in an unlocked configuration in accordance withembodiments of the present invention;

FIG. 7 is a cross-sectional view of a locking clamp assembly disposed ina tulip element in a locked configuration in accordance with embodimentsof the present invention;

FIG. 8 is a top view of a tulip element in accordance with embodimentsof the present invention;

FIG. 9 is a top view of a locking cap assembly in accordance withembodiments of the present invention;

FIG. 10 is a perspective view of a locking cap assembly in accordancewith embodiments of the present invention;

FIG. 11 is a cross-sectional view of a locking cap assembly inaccordance with embodiments of the present invention;

FIGS. 12-14 illustrate an alternative orthopedic fixation device inaccordance with embodiments of the present invention;

FIGS. 15-16 illustrate another alternative orthopedic fixation device inaccordance with embodiments of the present invention;

FIGS. 17-19 illustrate yet another alternative orthopedic fixationdevice in accordance with embodiments of the present invention;

FIGS. 20-22 illustrate yet another alternative orthopedic fixationdevice in accordance with embodiments of the present invention;

FIG. 23 illustrates an orthopedic fixation device comprising a bone hookin accordance embodiments of the present invention;

FIGS. 24-25 illustrate an alternative wedge element in accordance withembodiments of the present invention;

FIG. 26 illustrates an offset iliac connector in accordance withembodiments of the present invention;

FIGS. 27-29 illustrate a bone fastener having a threaded instrumentinterface in accordance with embodiments of the present invention;

FIG. 30 illustrates a cross-sectional view of a vertebra having anorthopedic fixation device installed therein in accordance withembodiments of the present invention;

FIG. 31 illustrates a cross-sectional view of a uniplanar tulip assemblyin accordance with embodiments of the present invention;

FIG. 32 illustrates a disassembled view of portions of the uniplanartulip assembly in accordance with embodiments of the present invention;

FIG. 33A illustrates a bottom perspective view of a uniplanar ringelement in accordance with embodiments of the present invention;

FIG. 33B illustrates a side view of the uniplanar ring element of FIG.33A;

FIG. 33C illustrates a top view of the uniplanar ring element of FIG.33A;

FIG. 33D illustrates another side view of the uniplanar ring element ofFIG. 33A;

FIG. 34 illustrates a side view of a clamp element mated to a uniplanarring element in accordance with embodiments of the present invention;

FIG. 35 illustrates a side view of a wedge element mated with a clampelement in accordance with embodiments of the present invention;

FIG. 36 illustrates an alternate side view of the wedge element matedwith the clamp element in FIG. 35;

FIG. 37 illustrates a top perspective view of the wedge element matedwith the clamp element in FIG. 35;

FIG. 38 illustrates a top view of a wedge element in accordance withembodiments of the present invention;

FIG. 39A illustrates a uniplanar tulip assembly in an unlocked positionin accordance with embodiments of the present invention;

FIG. 39B illustrates the uniplanar tulip assembly of FIG. 38A in alocked position.

FIG. 40 illustrates a cross-sectional view of a fracture screw withuniplanar ring element in accordance with embodiments of the presentinvention; and

FIG. 41 illustrates a perspective view of a uniplanar locking assemblyfor the fracture screw of FIG. 40.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are generally directed toorthopedic fixation devices configured for bottom loading of the bonefastener. Instead of loading the bone fastener from the top of the tulipelement, embodiments of the present invention load the bone fastenerfrom the bottom of the tulip element. With the bone fastener loaded inthe tulip element, a locking clamp assembly can then be used to securethe bone fastener therein. Thus, unlike prior orthopedic fixationdevices, embodiments of the present invention permit the use of largerbone fasteners without having to also increase the size of the tulipelement. This should, for example, reduce the needed inventory,decreasing the necessary graphic cases needed to perform a similarprocedure, while decreasing in-house inventory costs.

Further, as explained by the examples and illustrations below, the bonefastener of the orthopedic fixation devices can be placed in thevertebra without the tulip element in accordance with embodiments of thepresent invention. The tulip element can then be attached to the bonefastener in situ. This should reduce the material in the surgical wound,thus increasing visualization for disc preparation and interbodyprocedures, for example. The bone fastener can also be used to distractor otherwise manipulate the surgical site, further increasingvisualization and ease of surgery, for example. Additionally, sitepreparation can be performed, in some embodiments, after the bonefastener has been placed, which may allow for more accurate pedicledecortication.

Turning now to FIG. 1, an exploded view of an orthopedic fixation device2 is illustrated in accordance with embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 may comprisea bone fastener 4, a locking clamp assembly 6 (which may comprise, forexample, a clamp element 7 and a wedge element 8), a tulip element 10,and a locking cap assembly 12. As will be discussed in more detailbelow, the bone fastener 4 may be loaded from the bottom of the tulipelement 10 with the locking clamp assembly 6 already loaded therein.Prior to being locked into place, the tulip element 10 can be moved androtated into a plurality of positions with respect to the bone fastener4. Once the tulip element 10 is at the desired position with respect tothe bone fastener 4, the tulip element 10 may be locked onto the bonefastener 4. In the illustrated embodiment, the locking cap assembly 12is configured to secure a rod 14 in the tulip element 10. In oneembodiment, the tulip element 10 is fixed onto the bone fastener 4contemporaneously with securing of the rod 14 in the tulip element 10.

As illustrated by FIG. 1, the bone fastener 4 includes a head 16 and ashaft 18 that extends from the head 16. The illustrated embodiment showsthe shaft 18 having a tapered shape and threads 20. Those of ordinaryskill in the art will appreciate that the shaft 18 may have a number ofdifferent features, such as thread pitch, shaft diameter to threaddiameter, overall shaft shape, and the like, depending, for example, onthe particular application. While the head 16 may have any generalshape, at least a portion of the head 16 may have a curved surface inorder to allow for rotational movement or angular adjustment of the bonefastener 4 with respect to the tulip element 10. For example, at least aportion of the head 16 may be shaped to form a portion of a ball or atleast a portion of a sphere. As illustrated, the head 16 may have aroughened or textured surface 22 that improves engagement with the clampelement 7. In certain embodiments, the head 16 may have a toolengagement surface, for example, that can be engaged by a screw-drivingtool or other device. The tool engagement surface can permit thephysician to apply torsional or axial forces to the bone fastener 4 todrive the bone fastener 4 into the bone. In the illustrated embodiment,the tool engagement surface of the head 16 is a polygonal recess 24. Forinstance, the polygonal recess 24 may be a hexagonal recess thatreceives a hexagonal tool, such as an allen wrench, for example. Thepresent invention is intended to encompass tool engagement surfaceshaving other shapes, such as slot or cross that may be used, forexample, with other types of screwdrivers. In an alternative embodiment(not illustrated), the engagement surface may be configured with aprotruding engagement surface that may engage with a tool or devicehaving a corresponding recess.

Referring now to FIGS. 1-3, clamp element 7 of the locking clampassembly 6 will be described in more detail in accordance withembodiments of the present invention. As illustrated, the clamp element7 includes a first clamp portion 26 and a second clamp portion 28. Inthe illustrated embodiment, the first clamp portion 26 is substantiallyidentical to and a mirror image of, the second clamp portion 28. Thefirst and second clamp portions 26, 28 provide a collar about the head16 of the bone fastener 4, when installed, as discussed in more detailbelow. The first and second clamp portions 26, 28 grip bone fastener 4when force is applied onto the clamp element 7 by the tulip element 10.While the embodiments that are described and illustrated generallydescribe the first and second clamp portions 26, 28 as substantiallyidentical, the portions 26, 28 may be of varying size and are notrequired to be mirror images of one another. In addition, while theclamp element 7 is illustrated as having two clamp portions (first andsecond clamp portions 26, 28), the clamp element 7 may comprise morethan two portions for gripping the bone fastener 4.

As illustrated, each of the first and second clamp portions 26, 28includes an outer surface 30, 32, which may be curved or rounded, asbest shown in FIGS. 1 and 2. The outer surfaces 30, 32 of the first andsecond clamp portions 26, 28 may each include an outer tapered surface34, 36. In addition, the outer surfaces 30, 32 may each also have atleast one slit 38 formed therein. The at least one slit 38 may, forexample, allow the first and second clamp portions 26, 28 to constrictand securely engage the head 16 of the bone fastener 4. The outersurfaces 30, 32 should abut and engage the inner wedge surface 86 of thetulip element 10 when fully installed and locked in place in the tulipelement 10 in accordance with present embodiments. With particularreference to FIG. 3, the first and second clamp portions 26, 28 eachinclude inner surfaces 38, 40. When fully installed and locked in placein the tulip element 10, the inner surfaces 38, 40 should abut andengage the head 16 of the bone fastener 4 in accordance with presentembodiments. The illustrated embodiment shows the inner surfaces 38, 40having roughened or textured features 22 that improve engagement withthe head 16 of the bone fastener 4. The first and second clamp portions26, 28 each may also include an external lip 46, 48, which may belocated above the outer tapered surfaces 34, 36, as best seen in FIG. 3.The first and second clamp portions 26, 28 each may also include anupper surface 31, 33, as best seen in FIG. 1.

Referring now to FIGS. 1-5, the wedge element 8 of the locking clampassembly 6 will be described in more detail in accordance withembodiments of the present invention. As illustrated, the wedge element8 may include a bore 50. The lower portion of the bore 50 may be sizedto receive the upper portion of the clamp element 7, including externallips 46, 48 of the first and second clamp portions 26, 28. The wedgeelement further may include an outer surface 52 having a recessedportion 54. The outer surface 52 may be generally rounded, for example.As best seen in FIG. 4, the outer surface 52 of the wedge element 8 maybe generally elliptical, in one embodiment. The elliptical shape of theouter surface 52 should, for example, limit radial motion of the wedgeelement when installed in the tulip element 10. The wedge element 8further may include an upper surface 56. In the illustrated embodiment,the upper surface 56 defines a seat that receives the rod 14. Asillustrated, the upper surface 56 may be generally convex in shape. Inthe illustrated embodiment, the wedge element 8 further includes anupper lip 57.

With particular reference to FIG. 3, the wedge element 8 furtherincludes an inner wedge surface 58. As illustrated, the inner wedgesurface 58 may be disposed around a lower portion of the bore 50. In oneembodiment, the inner wedge surface 58 forms a conical wedge. The innerwedge surface 58 operates, for example, to engage the outer taperedsurfaces 34, 36 of the first and second clamp portions 26, 28 to forcethe clamp element 7 down the bore 62 of the tulip element 10. The wedgeelement 8 further may include an inner protruding surface 60 adjacent tothe inner wedge surface 58 and an inner recessed surface 62 adjacent theinner protruding surface 60. The wedge element 8 further may include aninner seat 64. As illustrated, the inner seat 64 may be downwardlyfacing for receiving upper surfaces 31, 33 of the first and second clampportions 26, 28. In an embodiment, the inner seat 64 restricts or limitsmovement of the clamp element 4 through the bore 50 of the wedge element8.

In accordance with present embodiments, the locking clamp assembly 6 canbe assembled prior to insertion into the tulip element 10. In oneembodiment, for assembly, the clamp element 7 may be inserted into thewedge element 8 upwardly through the bore 50. The outer surfaces 30, 32of the first and second clamp portions 26, 28 should slidingly engagethe inner wedge surface 58 of the wedge element 8 as the clamp element 7is inserted. The clamp element 7 should be inserted until the externallips 46, 48 of the first and second clamp portions 26, 28 pass the innerprotruding surface 60 of the wedge element 8. The inner protrudingsurface 60 engages the external lips 46, 48 to secure the clamp element7 in the wedge element 8. In the illustrated embodiment, the lockingclamp assembly 6 will not fit downwardly through the top of the bore 62of the tulip element 10 as the locking clamp assembly has an outerdiameter at its biggest point that is larger than the inner diameter ofthe upper portion of the bore 62.

Referring now to FIGS. 1 and 6-8, the tulip element 10 will be describedin more detail in accordance with embodiments of the present invention.As illustrated, the tulip element 10 may comprise bore 62, a body 65 andarms 66 that extend upwardly from the body 65. In the illustratedembodiment, the arms 66 define a U-shaped channel 68 sized to receivethe rod 14. Each of the arms 66 has an interior surface 70 the interiorsurface 70 having a threaded portion 72 for engaging correspondingthreads on a screw-driving tool (e.g., tool 144 on FIGS. 27-29). Theinterior surface 70 of each of the arms 66 further may include a slot 74for receiving corresponding tabs 96 (e.g., FIG. 9) of the locking capassembly 12 and a recessed surface 76 for engaging correspondingprotuberances 100 (e.g., FIG. 9) of the locking cap assembly 12. Asillustrated, the recessed surface 76 of each of the arms 66 may belocated above the slot 74. The interior surface 70 of each of the arms66 further may include a protuberance 78. In the illustrated embodiment,the protuberance 78 of each of the arms 66 is located below the threadedportion 72 with the threaded portion 72 being located between theprotuberance 78 and the slot 74. As best seen in FIG. 6, the interiorsurface 70 of each of the arms 66 further may form a downwardly facingseat 79, for example, which may limit or restrict movement of thelocking clamp assembly 6 through the bore 62. Each of the arms 66further may include an outer surface 80. The outer surface 80 of each ofthe arms 66 may include a tool engagement groove 82 formed on the outersurface 80 which may used for holding the tulip element 10 with asuitable tool (not illustrated).

As illustrated, the body 65 of the tulip element 10 may have an outersurface 84, which may be curved or rounded, as best seen in FIG. 1. Withparticular reference to FIGS. 6 and 7, the body 65 further may includean inner wedge surface 86 disposed around a lower portion of the bore62. In one embodiment, the inner wedge surface 86 forms a conical wedge.The inner wedge surface 86 of the body 65 of the tulip element 10, forexample, may abut and engage the outer surfaces 30, 32 of the first andsecond clamp portions 26, 28 when the locking clamp assembly 6 is fullyinstalled and locked in place.

In accordance with present embodiments, the locking clamp assembly 6 maybe installed in the tulip element 10 in either an unlocked position or alocked position. FIG. 6 illustrates the locking clamp assembly 6disposed in the tulip element 10 in the unlocked position in accordancewith embodiments of the present invention. In FIG. 6, the locking clampassembly 6 has been inserted into the tulip element 10 upwardly throughthe bore 62. The locking assembly 6 should be inserted until the upperlip 57 of the wedge element 8 passes the protuberances 78 located on theinterior surfaces 70 of the arms 66 of the tulip element 10. Theprotuberances 78 should engage the upper lip 57 to secure the lockingclamp assembly 6 in the tulip element 10. While not illustrated on FIG.6, the bone fastener 4 (e.g., shown on FIG. 1) can now be placed intothe locking assembly 6 through a snap fit with the clamp element 7.There should be sufficient clearance for the clamp element 7 to expandand snap around the head 16 of the bone fastener 4. The locking clampassembly 6 and the tulip element 10, however, should still be free torotate with respect to the bone fastener 4. The tulip element 10 can bemoved and rotated to obtain a desired portion with respect to the bonefastener 4. The locking clamp assembly 6 should also move with the tulipelement during rotation of the tulip element 10 with respect to the bonefastener 4. Once the tulip element 10 is at the desired position, thetulip element 10 may be locked onto the bone fastener 4. The lockingclamp assembly 6 and the tulip element 10 should cooperate to lock theclamp assembly 6 onto the head 16 of the bone fastener 4.

FIG. 7 illustrates the locking clamp assembly 6 disposed in the tulipelement 10 in the locked position in accordance with embodiments of thepresent invention. In FIG. 7, the locking clamp assembly 6 has beenpushed downwardly in the bore 62 of the tulip element 10. Asillustrated, the locking clamp assembly 6 has been pushed downward untilthe upper lip 57 of the wedge element 8 passes the protuberances 78located on the interior surfaces 70 of the arms 66 of the tulip element10. As the locking clamp assembly 6 moves downward, the clamp element 7engages the body 65 of the tulip element 10. As illustrated, the outersurfaces 30, 32 of the first and second clamp portions 26, 28 of theclamp element 7 should abut and engage the inner wedge surface 86 of thebody 65 of the tulip element 10, forcing inner surfaces 38, 40 of thefirst and second clamp portions 26, 28 to engage head 16 of the bonefastener 4 (e.g., FIG. 1). In the locked position, tulip element 10should be locked onto the bone fastener 4, thus preventing furtherpositioning of the tulip element 10 with respect to the bone fastener 4.

Referring now to FIGS. 1 and 9-11, the locking cap assembly 12 will bedescribed in more detail in accordance with embodiments of the presentinvention. As illustrated, the locking cap assembly 12 may comprise abody 88 and a set screw 90 threaded into a bore 92 in the body 88. Theset screw 90 may have a length, for example, that is longer than thelength of the bore 92. In the illustrated embodiment, at least a portionof the set screw 90 extends from the top of the body 88. In certainembodiments, the set screw 90 may have a tool engagement surface, forexample, that can be engaged by a screw-driving tool or other device.The tool engagement surface can permit the physician to apply torsionalor axial forces to the set screw 90 to advance the set screw 90 throughthe body 88 and onto the rod 14. When the locking cap assembly 12 is inits locked position, the set screw 90 can be advanced through the body88 to engage the rod 14, applying downward force onto the rod 14 andsecuring it to the tulip element 12. In one embodiment, the set screw 90forces the rod 14 downward and into contact with the locking clampassembly 6 causing the locking cap assembly 6 to move downward in thetulip element 10. In the illustrated embodiment, the tool engagementsurface of the set screw 90 is a polygonal recess 94. For instance, thepolygonal recess 94 may be a hexagonal recess that receives a hexagonaltool, such as an allen wrench, for example. The present invention isintended to encompass tool engagement surfaces having other shapes, suchas slot or cross that may be used, for example, with other types ofscrewdrivers. In an alternative embodiment (not illustrated), theengagement surface may be configured with a protruding engagementsurface that may engage with a tool or device having a correspondingrecess.

In accordance with present embodiments, the body 88 may have one or moreprojections. For example, the body 88 may comprise lower tabs 96projecting radially from a lower end of the body 88. In the illustratedembodiment, the body 88 comprises a pair of lower tabs 96 located onopposite sides of the body 88. As illustrated, the lower tabs 96 mayeach have an outer surface 98 that is generally rounded in shape. Inaddition, while the body 88 is illustrated as having two lower tabs 96,the body 88 may comprise more than two lower tabs 96. As illustrated,the body 88 further may comprise protuberances 100. The protuberances100 may engage with corresponding recessed surface 76 (e.g., FIG. 10) ofthe arms 66 of the tulip element 10. The protuberances 100 may becapable of providing a tactile or audible signal to the physician, suchas a click that may be felt or heard, when the locking cap assembly 12has reached its locking position. The protuberances 100 also may assistin maintaining the locking cap assembly 12 in its locked position. Inthe illustrated embodiment, the body 88 further may comprise toolengagement features. The tool engagement features may, for example, beused for holding or manipulating the locking cap assembly 12 with asuitable tool (not illustrated). In the illustrated embodiment, thelocking cap assembly 12 includes upper tabs 102. As illustrated, thetabs 102 may be formed at the upper surface of the body 88. In theillustrated embodiment, the locking cap assembly 12 includes four uppertabs 102 at the corners of the upper surface. In addition, while thebody 88 is illustrated as having four upper tabs 102, the body 88 maycomprise more or less than four upper tabs 102.

To place the locking cap assembly 12 onto the tulip element 10, thelower tabs 96 should be aligned with the u-shaped channel 68 formed bythe arms 66 of tulip element 10 and the locking cap assembly 12 can thenbe lowered downward into the bore 62 in the tulip element 10. Once thelower tabs 96 are aligned with the corresponding slots 74 in the arms 66of the tulip element 10, the locking cap assembly 12 can be rotated. Theslots 74 allow the lower tabs 96 to pass through the arms 66 when thelower tabs 96 and the slots 74 are aligned. The length of the slots 74generally correspond to the amount of rotation needed to move thelocking cap assembly 12 into or out of a locked position. In oneembodiment, the locking cap assembly 12 rotates from about 60° to about120° for placement into a locking positions, alternatively, about 80° toabout 100°, and, alternatively, about 90°. As previously mentioned, theprotuberances 100 can be configured to provide a tactile or audiblesignal to the physician when the locking cap assembly 12 has reached itslocked assembly. In addition, the protuberances 100 can also assist inmaintaining the locking cap assembly 12 in its locked position. Otherfeatures such as undercuts and geometric mating surfaces may be used toprevent rotation in the opposite direction. With the locking capassembly 12 locked in place, the set screw 94 can then be rotated. Asthe set screw 94 moves downward and extends from the bottom of the base88 of the locking cap assembly 12, the set screw 94 presses against therod 14 securing it in the tulip element 10. In addition, the rod 14 mayalso be pressed downward into engagement with the locking clamp assembly6 forcing it downward in the tulip element 10. As the locking clampassembly 6 moves downward, the clamp element 7 engages the body 65 ofthe tulip element 10. As best seen in FIG. 7, the outer surfaces 30, 32of the first and second clamp portions 26, 28 of the clamp element 7should abut and engage the inner wedge surface 86 of the body 65 of thetulip element 10, forcing inner surfaces 38, 40 of the first and secondclamp portions 26, 28 to engage head 16 of the bone fastener 4 andsecure it with respect to the tulip element 10.

Referring now to FIGS. 12-14, locking of the tulip element 10 onto thebone fastener 4 is illustrated in more detail in accordance withembodiments of the present invention. For the purposes of thisillustration, the locking cap element 12 (e.g., FIG. 1) is not shown.The tulip element 10 shown in FIGS. 12-14 is similar to the tulipelement 10 described previously except that the tulip element 10 doesnot include a threaded portion 72 (e.g., FIGS. 6-7) or a downwardlyfacing seat 79 (e.g., FIG. 6) in the interior surface 70 of the arms 66of the tulip element 10. FIG. 12 illustrates the locking clamp assembly6 installed in the tulip element 10 in an unlocked position. Aspreviously mentioned, the locking clamp assembly 6 can be inserted intothe tulip element 10 upwardly through the bore 62. As shown in FIG. 12,the locking assembly 6 should be inserted until the upper lip 57 of thewedge element 8 passes the protuberances 78 located on the interiorsurfaces 70 of the tulip element 10. The protuberances 78 should engagethe upper lip 57 to secure the locking clamp assembly 6 in the tulipelement 10. As illustrated by FIG. 13, the bone fastener 4 can now beplaced into the locking assembly 6 through a snap fit with the clampelement 7. There should be sufficient clearance for the clamp element 7to expand and snap around the head 16 of the bone fastener 4. Thelocking clamp assembly 6 and the tulip element 10, however, should stillbe free to rotate with respect to the bone fastener 4. The tulip element10 can be moved and rotated to obtain a desired portion with respect tothe bone fastener 4. Once the tulip element 10 is at the desiredposition, the tulip element 10 may be locked onto the bone fastener 4.The locking clamp assembly 6 and the tulip element 10 should cooperateto lock the clamp assembly 6 onto the head 16 of the bone fastener 4.

FIG. 14 illustrates the locking clamp assembly 6 disposed in the tulipelement 10 in the locked position and clamping onto the bone fastener 4to secure the bone fastener 4 with respect to the tulip element 10 inaccordance with embodiments of the present invention. As seen in FIG.14, the locking clamp assembly 6 has been pushed downwardly in the bore62 of the tulip element 10 until the upper lip 57 of the wedge element 8passes the protuberances 78 located on the interior surfaces 70 of thearms 66 of the tulip element 10. As the locking clamp assembly 6 movesdownward, the clamp element 7 engages the body 65 of the tulip element10 such that the outer surfaces 30, 32 of the first and second clampportions 26, 28 of the clamp element 7 should abut and engage the innerwedge surface 86 of the body 65 of the tulip element 10, forcing innersurfaces 38, 40 of the first and second clamp portions 26, 28 to engagehead 16 of the bone fastener 4. In the locked position, tulip element 10should be locked onto the bone fastener 4, thus preventing furtherpositioning of the tulip element 10 with respect to the bone fastener 4.

Referring now to FIGS. 15 and 16, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. As previously mentioned, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8. Asillustrated, the clamp element 7 may include a first clamp portion 26and a second clamp portion 28. In the illustrated embodiment, the firstand second clamp portions 26, 28 each include an inner tapered surface106, 108 such that the lower portions of the first and second clampportions 26, 28 can expand when pressure is applied that constricts theupper portion of the first and second clamp portions 26, 28. Incontrast, to the wedge element 8 that was previously described,embodiments of the upper surface 56 of the wedge element 8 illustratedon FIGS. 15 and 16 do not define a seat that receives the rod 14 (e.g.,FIG. 1), but rather are generally planar with bore 50 penetrating therethrough. As illustrated, the wedge element 8 further includes an innerwedge surface 58 formed around a lower portion of the bore 50. As alsopreviously mentioned, the tulip element 10 generally may comprise a bore62, base 64, and arms 66. The inner diameter of the bore 62 in the upperportion of the tulip element 10 may be made smaller than either thecombined size of the clamp element 7 and the bone fastener 4 or thediameter of the shaft 14 of the bone fastener 4, whichever is larger. Asillustrated, the arms 66 may each comprise an interior surface 70. Inthe illustrated embodiment, the interior surface 70 includes innertapered surface 104 rather than a downwardly facing seat 79 (e.g., FIG.6) in the interior surface 70 of the arms 66 of the tulip element 10.

With continued reference to FIGS. 15 and 16, locking of the tulipelement 10 onto the bone fastener 4 will be described in more detail inaccordance with embodiments of the present invention. The first andsecond clamp portions 26, 28 of the clamp element 7 may be inserted oneafter another upwardly into the bore 62 of the tulip element 10. Thefirst and second clamp portions 26, 28 may be pushed axially towards thetop of the tulip element 10. The first and second clamp portions 26, 28should continue to move upwardly until they engage the inner taperedsurface 104 of the tulip element 10. Due the taper angle of the innertapered surface 104, the upper portion of the first and second clampportions 26, 28 will be forced to move inwards until the inner taperedsurfaces 106, 108 of each of the first and second clamp portions 26, 28come into contact. This contraction at the top of the first and secondclamp portions 26, 28 should result in a wider opening at the bottom ofthe clamp element 7. The bone fastener 4 can then be inserted throughthe bottom of the bore 62 of the tulip element 10 and into the clampelement 7. The bone fastener 4 can then be manipulated, for example, tocenter the clamp element 7 into the head 16 of the bone fastener 4. Thetulip element 10, however, should still be free to rotate with respectto the bone fastener 4. The tulip element 10 can be moved and rotated toobtain a desired portion with respect to the bone fastener 4. Once thetulip element 10 is at the desired position, the tulip element 10 may belocked onto the bone fastener 4.

To lock the tulip element 10, the bone fastener 4 can be pulled downwardand because the clamp element 7 is in engagement with the bone fastener4, the clamp element 7 should also move downward in the tulip element 10such that the clamp element 7 engages the body 65 of the tulip element10. As illustrated, the outer surfaces 30, 32 of the first and secondclamp portions 26, 28 of the clamp element 7 should abut and engage theinner wedge surface 86 of the body 65 of the tulip element 10, forcinginner surfaces 38, 40 of the first and second clamp portions 26, 28 toclamp onto the head 16 of the bone fastener 4. The wedge element 8 canthen be introduced downwardly from the top of the bore 62 in the tulipelement 10 to seat on top of the clamp element 7. The wedge element 8should engage the interior surfaces 70 of the tulip element 10preventing upward movement of the clamp element 7, locking the clampelement 7 in its engagement with the head 16 of the bone fastener. Inthe locked position, the tulip element 10 should be locked onto the bonefastener 4, thus preventing further positioning of the tulip element 10with respect to the bone fastener 4.

Referring now to FIGS. 17-19, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, a locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8. Theorthopedic fixation device 2 is similar to the embodiments of FIGS.15-16 except that embodiments of the wedge element 8 include downwardlyextending tabs 110 that fits into corresponding slots 112 in the top ofthe head 16 of the bone fastener 4. In general, the tabs 110 shouldimpart a uni-planar restraint on the bone fastener 4 so that it onlyslides along mating surfaces. The interior surfaces 114 of the tabs 110,best seen in FIG. 19, should forms the sides of the internal drivingfeatures. In an alternative embodiment (not illustrated), the wedgeelement 8 can be configured so that the tabs 110 are interconnected, forexample, to impart more strength to the design of the wedge element 8.

Referring now to FIGS. 20-21, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, a locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8.

The orthopedic fixation device 2 is similar to the embodiments of FIGS.15-16 except that embodiments of the clamp element 7 are configured fortop loading from the top of the bore 62 in the tulip element 10. Insteadof being inserted upwardly from the bottom of the bore 62, the first andsecond clamp portions 26, 28 of the clamp element 7 are inserteddownwardly from the top of the bore 62, until the clamp portions 26, 28engage the inner wedge surface 86 of the body 65 of the tulip element10. The bone fastener 4 can then be inserted upwardly from the bottom ofthe bore 62 of the tulip element 10 and into engagement with the clampelement 7 whereby the clamp element 7 will be pushed upwardly towardsthe top of the tulip element 10. The clamp element 7 will move higheruntil they engage an external temporary stop (not illustrated) thatprevents further upward movement. As the clamp element 7 moves higher inthe tulip element 10, the clamp portions 26, 28 adjust and reorient dueto increased clearance with the inner wedge surface 86 of the tulipelement 10 such that the opening at the bottom of the clamp element 7 islarger than the diameter of the head 16 of the bone fastener 4.

To lock the tulip element 10, the bone fastener 4 can be pulled downwardand because the clamp element 7 is in engagement with the bone fastener4, the clamp element should also move downward in the tulip element 10such that the outer surfaces 30, 32 of the first and second clampportions 26, 28 of the clamp element 7 should abut and engage the innerwedge surface 86 of the body 65 of the tulip element 10, forcing innersurfaces 38, 40 of the first and second clamp portions 26, 28 to clamponto the head 16 of the bone fastener 4. In accordance with presentembodiments, the smallest inner diameter for the bore 62 in the tulipelement 10 is smaller than the combined size of the clamp element 7 andthe head 16 of the bone fastener 4, when in engagement. The wedgeelement 8 can then be introduced downwardly from the top of the bore 62in the tulip element 10 to seat on top of the clamp element 7. The wedgeelement 8 should engage the interior surfaces 70 of the tulip element 10preventing upward movement of the clamp element 7, locking the clampelement 7 in its engagement with the head 16 of the bone fastener. Inthe locked position, the tulip element 10 should be locked onto the bonefastener 4, thus preventing further positioning of the tulip element 10with respect to the bone fastener 4.

Referring now to FIG. 22, an orthopedic fixation device 2 is describedin accordance with alternative embodiments of the present invention. Asillustrated, the orthopedic fixation device 2 comprises a locking clampassembly 6 and a tulip element 10. For the purposes of thisillustration, the bone fastener (e.g., FIG. 1) and locking cap assembly12 (e.g., FIG. 1) are not shown. In the illustrated embodiment, thelocking clamp assembly 6 comprises a clamp element 7 and a wedge element8.

The orthopedic fixation device 2 is similar to the embodiments of FIGS.20-21 except that embodiments of the wedge element 8 include a retentionfeature for coupling with the clamp element 7. As illustrated, the wedgeelement 8 includes an inner protruding surface 60 that engages with theexternal lips 46, 48 of the first and second clamp portions 26, 28 ofthe clamp element 7 to secure the clamp element 7 in the wedge element8. The locking clamp assembly 6 with the clamp element 7 secured in thewedge element 8 can then be inserted downwardly from the top of the bore62 in the tulip element 10, until the clamp portions 26, 28 engage theinner wedge surface 86 of the body 65 of the tulip element 10. Once thebone fastener 4 is snapped into the clamp element 7, the locking clampassembly 6 can be forced downwards through the tulip element 10 into itslocked position to secure the bone fastener (e.g., FIG. 1) in the clampelement 7. In the locked position, the tulip element 10 should be lockedonto the bone fastener 4, thus preventing further positioning of thetulip element 10 with respect to the bone fastener 4.

While the embodiments that are described and illustrated above generallyillustrate a bone fastener 4 in shape of a screw having a head 16 andshaft 18 extending there from, it should be understood that other bonefasteners may also be used such as hooks and sacral blocks. Thus, thepresent invention may be used with a wide variety of bone fasteners inaddition to a bone screw, as described above. For example, FIG. 23illustrates an embodiment in which the bone fastener 14 includes a head16 having an extension in the form of a hook 116 that extends from thehead 16. In the illustrated embodiment, the head 16 is secured in thetulip element 10 by the clamp element 7 and the wedge element 8. Asillustrated, the head 16 may have a roughened or textured surface 22that improves engagement with the clamp element 7.

FIGS. 24 and 25 illustrate a wedge element 8 having an optional rodretention feature, in accordance with embodiments of the presentinvention. In some embodiments, the rod retention feature of the wedgeelement 8 may be added to enhance retainment of the rod 14 (e.g.,FIG. 1) in a surgical procedure. In the illustrated embodiment, the rodretention feature is in the form of seat extensions 118 that will cradlethe rod 14 to retain it in the wedge element 8. As illustrated, thewedge element 8 comprises an upper surface 56 defining a seat forreceiving the rod 14. The wedge element 8 further may comprise seatextensions 118 for retaining the rod in the wedge element 8. In oneembodiment, the seat extensions 118 may be configured to flex when a rod14 is pushed down through opening 122 at the top of the seat extensions118. When pressed down, the rod 14 may engage the ends of the seatextensions 118 causing the seat extensions 118 to flex outwardincreasing the size of the opening so that the rod 14 can be moveddownwards to rest on the upper surface 56 of the wedge element 8. Inother words, the rod 14 may be snapped past the seat extensions 118 inaccordance with some embodiments. In the illustrated embodiment, thewedge element 8 further includes notches 122 to facilitate flexing ofthe seat extensions 118.

While the embodiments that are described and illustrated above generallyillustrate a tulip element 10 in the general shape of a “U” for couplingthe rod 14 to the bone fastener 4, it should be understood that any of avariety of different coupling elements may be used in accordance withembodiments of the present invention. For example, the coupling elementmay be open (e.g., tulip element 10 on FIG. 1) or closed. In someembodiments, the rod 14 may be top loaded into an open coupling element.In other embodiments, the rod 14 may be side loaded, for example, into aclosed coupling element. In some embodiments, the coupling element maybe an open, closed, or offset iliac connector. In yet other embodiments,the coupling element may be a posted screw connector. In addition, thecoupling element may be configured to move polyaxially, monoaxially, oruni-planar with respect to the bone fastener 4 prior to locking of thecoupling element onto the bone fastener 4.

FIG. 26 illustrates a coupling element in accordance with alternativeembodiments of the present invention. In the illustrated embodiment, thecoupling element is an offset iliac connector 124. The offset iliacconnector 124 should allow, for example, iliac screw placement prior toselection of coupling element type. The design of the offset iliacconnector 124 should also allow, for example, removal of the iliacconnector 124 using a specialized instrument (not illustrated) to changethe coupling element type in situ. As illustrated, the offset iliacconnector 124 includes an offset housing 126, a set screw 128, a springwasher 130, and a locking clamp assembly 132. In accordance withembodiments of the present invention, the set screw 128 can be installedthrough the bottom of the offset housing 126 and rotated (e.g., counterclockwise) until tight. After installation of the set screw 128, thespring washer 130 may then be inserted upwardly through the bottom ofthe offset housing 126. In the illustrated embodiment, the spring washer130 has a washer portion 134 and a spring portion 136 that extends downfrom the washer portion 134. The locking clamp assembly 132 may then beinserted upwardly through the bottom of the offset housing 126 andsnapped into a place, in a manner similar to the previously describedembodiments. In the illustrated embodiment, the locking clamp assembly132 includes a wedge element 138 and a clamp element 140. To engage theoffset connector with a head 16 of a bone fastener 4 (e.g., FIG. 1), theoffset connector can be pushed down onto the head 16. The head 16 of thebone fastener 4 should be pushed upward into the locking clamp assembly132. The bone fastener 4 should push the locking clamp assembly 132upward into the spring portion 136 of the spring washer 130 untilsufficient clearance is achieved between the locking clamp assembly 132and the offset housing 126 for the bone fastener 4 to snap into thelocking clamp assembly 132. The spring washer 130 should then providedownward force onto the locking clamp assembly 132 such that theinterior wedge surface 142 of the offset housing 126 applies pressure tothe locking clamp assembly 132 forcing the clamp element 138 to clamponto the head 16 of the bone fastener 4. In some embodiments, aspecialized instrument (not illustrate) can be threaded through thepolygonal recess 144 (e.g., a hexagonal recess) in the set screw 128 andinto the locking clamp assembly 132. The threading of the instrumentshould provide sufficient clearance with the offset housing 126 forremoval of the offset iliac connector 124 from the bone fastener 4without removal of the bone fastener 4 from the bone.

As previously illustrated and described with respect to FIG. 1, thetulip element 10 may include a threaded portion 72. FIGS. 27-29illustrate the threaded portion 72 of the tulip element 10 in moredetail. As illustrated, the tulip element 10 includes a body 65 and arms66. As best seen in FIG. 28, the arms 66 each include an interiorsurface 70 having a threaded portion 72. In accordance with presentembodiments, a bone fastener 4 can be secured to the tulip element 10.As illustrated, a tool 144, which may be, for example, a screw-drivingtool, can be placed through the bore 62 in the tulip element 10 and intoengagement with the tulip element 10 and the bone fastener 4. In theillustrated embodiment, the tool 144 includes a threaded portion 146that engages the threaded portion 72 of the tulip element 10. The tool144 further includes an engagement end 148 below the threaded portion 72that engages with the polygonal recess 24 (e.g., hexagonal) in the head16 of the bone fastener 4. In this manner, a rigid connection may beformed between the bone fastener 4 and the tool 144.

FIG. 30 illustrates installation of the orthopedic fixation device 2 ina vertebra 150 in accordance with embodiments of the present invention.As illustrated, the bone fastener 4 may be implanted into the vertebra150. The bone fastener 4 may then be secured to the tulip element 10using, for example, the locking clamp assembly 6. The tulip element 10can then be moved and rotated into a desired position with respect tothe bone fastener 4 and then locked onto the bone fastener 4. In oneembodiment, the tulip element 10 is fixed onto the bone fastener 4contemporaneously with securing the rod 14 to the tulip element 10 withthe locking cap assembly 12. In this manner, the rod 14 can be securedin a fixed position relative to the vertebra 150.

Additional embodiments of a locking clamp assembly and individualfeatures are shown in FIGS. 31-39. In these figures, the locking clampassembly is a uniplanar locking clamp assembly, whereby a screw in theuniplanar locking clamp assembly is capable of uniplanar motion.

In some surgeries, it may be desired to use more than one type of screw,such as a polyaxial screw and/or a uniplanar screw. In some cases, asurgeon may initially choose to use a certain type of screw, and thenchange course during surgery and alter the type of screw to be used. Forsystems that use polyaxial screws or uniplanar screws with fixed,unremovable tulip heads, this may require removing a screw completelyfrom a bone before replacing it with another screw. To solve thesedifficulties, the system described herein advantageously utilizesmodular tulip assemblies that are loaded on top of a screw, or in otherwords, accommodate bottom-loaded screws. These modular tulip assembliescan accommodate polyaxial motion or uniplanar motion between the tulipassemblies and the screw, and can simply be exchanged during the courseof a surgery. Accordingly, when a surgeon desires to replace one type ofscrew for another (e.g., polyaxial for uniplanar or vice versa), he cansimply remove the modular tulip component and replace it with another,while leaving the screw in place (e.g., in a vertebral body).

FIG. 31 illustrates a uniplanar tulip assembly that can be attached tothe top of a bone fastener. Advantageously, the uniplanar tulip assembly200 is a modular assembly that can be loaded onto a bone fastener 4,even when the bone fastener 4 is fixed in a bone member. The uniplanartulip assembly 200 comprises similar elements to the assembly shown inFIG. 1, including a tulip element 10 and a locking clamp assembly 206comprising a wedge element 208 and a clamp element 207. In addition tothese components, the assembly 200 includes a ring member 230 that isfixed to the clamp element 207. This ring member 230 effectivelyrestricts motion between the bone fastener 4 and the tulip element 10 tobe uniplanar.

The tulip element 10 is similar to the tulip element in FIG. 1, andincludes a pair of arms 66 that form a U-shaped channel for receiving arod 14 therebetween. In some embodiments, the interior walls of the arms66 include threaded portions 72 for engaging corresponding threads on ascrew-driving tool. Each of the arms 66 also includes a slot 74 forreceiving tabs of a locking cap assembly that can be placed on top ofthe rod 14.

Like the locking clamp assembly 6 in FIG. 1, the locking clamp assembly206 also includes a wedge element 208 operably attached to a clampelement 207. The integrated wedge element 208 and clamp element 207 arecapable of locking with the tulip element 10, similarly as describedwith respect to FIGS. 6 and 7.

The wedge element 208 comprises a bore therethrough that is sized toreceive an upper portion of the clamp element 207. The top surface ofthe wedge element 208 is a curved saddle portion for seating a rod 14therein.

The clamp element 207 is comprised of a first clamp portion 226 and asecond clamp portion 228. Like the clamp element 7 discussed above,outer surfaces of the first and second clamp portions 226, 228 canslidingly engage an inner surface of the wedge element 208. The clampelement 207 can be inserted until lips of the first and second clampportions 226, 228 pass an inner protruding surface of the wedge element208. The inner protruding surface engages the external lips to securethe clamp element 207 in the wedge element 208, thereby integrating thewedge element and the clamp element.

The outer surfaces of the clamp element 207 can include at least oneopening 240 for receiving a ring element (shown in FIG. 33A)therethrough. In some embodiments, the clamp element 207 includes twoopposing openings 240 on opposite side walls. In some embodiments, eachof the first and second clamp portions 226, 228 include an opening suchthat when the two portions are combined, a continuous opening 240 isformed on an outer surface of the clamp element 207.

A ring element 230 (shown in FIGS. 33A-33D) is configured to be receivedin the clamp element 207. The ring element 230 includes a pair ofprotrusions 233 that are each received in an opening in the clampelement 207. The protrusions 233 are configured to glide along theopenings 240 of the clamp element 207, thereby allowing for motion alonga plane of axis (e.g., axis A-A shown in FIG. 33C) between the pair ofprotrusions. In an orthogonal plane, the mating of the protrusions 233with the openings 240 of the clamp element 207 prevents motion of thescrew head in that plane, thereby restricting the motion to be uniplanarmotion. Advantageously, in some embodiments, the addition of the ringelement 230 to the tulip assembly can convert a modular polyaxial tulipassembly into a uniplanar tulip assembly. More details regarding thering element 230 are discussed below with respect to FIGS. 33A-33D.

The uniplanar locking clamp assembly 206 is assembled as follows. Theclamp element 207 is first assembled with the ring element 230, and thenthe wedge element 208, prior to assembly with the tulip element 10. Thering element 230 is inserted into the mating thru-cuts or openings 240formed in the clamp element 207. The saddle or wedge element 208 ismated to the clamp element 207 through a snap-fit feature, creating auniplanar locking assembly 206. The uniplanar locking assembly 206 canthen be inserted into the tulip element 10, similarly to as discussedabove with respect to FIGS. 6 and 7.

FIG. 32 illustrates a disassembled view of portions of the uniplanartulip assembly in accordance with embodiments of the present invention.From this view, one can see the lips 246 of the clamp element 207 thatare mateable with the saddled wedge element 208. In addition, from thisview, one can see an upper surface of the clamp element 207, whichincludes a protruding feature 245. In some embodiments, each of theclamp portions 226 and 228 includes a protruding feature 245 that fitsinto a corresponding mating cut formed in the wedge element 208. Theprotruding features 245 advantageously maintain the orientation betweenthe clamp element 207 and the wedge element 208. These features 245 keepthe uniplanar locking clamp assembly 206 aligned throughout bothassembly and use.

FIGS. 33A-33D illustrate different views of a ring element 230 withprotrusions 233 according to some embodiments. The ring element 230includes an internal opening 237 for receiving the head of a screwfastener 4. The head of the screw fastener 4 is capable of movement inthe ring element 230; however, such movement is restricted to uniplanarmovement due to the engagement between the ring element protrusions 233and the openings 240 in the clamp element 207. In some embodiments, theprotrusions 233 have curved upper and lower surfaces, such that thegliding motion of the ring element 230 in the openings 240 can be in anarc. In other embodiments, the protrusions 233 have flat upper and lowersurfaces, such that the gliding motion of the ring element 230 in theopenings 240 can be substantially straight. In addition, in someembodiments, the lowest surfaces of the protrusions 233 are raisedslightly above the lowest surfaces of the base of the ring element 230.

FIG. 34 illustrates a side view of the ring element 230 mated to theclamp element 207. From this view, one can see how the protrusions 233of the ring element 230 are curved, and how the openings 240 in theclamp element 207 are also curved to provide for glided motion of theprotrusions that is an arc.

FIG. 35 illustrates a side view of the wedge element 208 mated with theclamp element 207. From this view, one can see how lips of the clampelement 207 mate with recesses of the wedge element 208 to secure theclamp element 207 (including a ring element 230) to the wedge element208.

FIG. 36 illustrates an alternate side view of the wedge element 208mated with the clamp element 207. From this view, one can see theprotruding feature 245 that extends from an upper surface of the clampelement 207 to maintain a desired orientation and alignment between theclamp element 207 and the wedge element 208.

FIG. 37 illustrates a top perspective view of the wedge element 208mated with the clamp element 207 with the ring element absent. From thisview, one can see how the opening 240 for receiving a ring elementprotrusion is visible even when the wedge element 208 is mated with theclamp element 207.

FIG. 38 is a top view of a saddle or wedge element 208 for use in theuniplanar locking clamp assembly. The wedge element 208 is configured toinclude one or more cut-outs that can receive one or more protrudingfeatures 245 that extend from an upper surface of the clamp element 207,thereby maintaining a desired orientation and alignment between theclamp element 207 and the wedge element 208.

FIGS. 39A and 39B illustrate the uniplanar locking clamp assembly in anunlocked and a locked position, respectively. While the uniplanarlocking clamp assembly 200 differs from the assembly in FIGS. 6 and 7,as it includes a tulip element 10, wedge element 208, clamp element 207and the additional ring element 230, positioning the uniplanar lockingassembly 200 in the unlocked and locked positions is performed similarlyas discussed above. In some embodiments, the uniplanar locking clampassembly 200 can be easily removed from a screw head during surgery, andcan be replaced with a different type of modular clamp assembly. In someembodiments, to remove the uniplanar locking clamp assembly 200, aremoval instrument can have a distal end that mates and lodges inrevolve cuts/relief areas 77 (shown in FIG. 2). The removal instrumentwill cause the expansion of the wedge element and/or clamp element,while allows the entire locking assembly 200 to translate up or down,thereby locking or unlocking the tulip element to the screw head. Such aremoval can be performed on any of the tulip elements, including thepolyaxial and uniplanar elements, described above.

FIG. 40 illustrates a cross-sectional view of a fracture screw assemblywith a uniplanar ring element in accordance with some embodiments. Thefracture screw assembly 300 can be used to provide controlled movementof one vertebrae in order to increase or decrease sagittal curves in thespine (e.g., kyphosis or lordosis). In some embodiments, the fracturescrew assembly 300 is similar to the uniplanar screw assembly 200described above, and includes a wedge element 308, a clamp element 307,and a ring element 330 therein; however, unlike the ring element 230that restricts motion along the axis of the rod slots to be uniplanarmotion, the ring element 330 restricts motion along an axis that isorthogonal to the rod slots. Each of the openings 340 in the clampelement 307 for receiving the ring element 330 are thus placed atapproximately 90 degrees with respect to an opening in the clamp element207 shown in previous embodiments.

FIG. 41 illustrates a perspective view of a uniplanar locking assemblyfor the fracture screw of FIG. 40. From this view, one can see how thesaddle or wedge element 308 substantially, or in some cases completely,covers the openings 340 in the clamp element 307 when the wedge element308 and clamp element 307 are assembled.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. A method of stabilizing a spine comprising:inserting a fixation system into a bone, the fixation system comprising:a fastener including a shaft member and a head member; and a tulipassembly attachable to the head member of the fastener, the tulipassembly including: a tulip element including a pair of arms forming achannel for receiving a rod member therein; a wedge element received inthe tulip element; a clamp element attachable to the wedge element, theclamp element including at least one opening for receiving portions of aring element therein; and a ring element having protrusions forinserting into the at least one opening in the clamp element, fixatingthe rod to member to the tulip assembly.
 2. The method of claim 1,wherein the at least one opening in the clamp element is curved.
 3. Themethod of claim 1, wherein the clamp element includes at least twoopenings, each for receiving a protrusion of the ring element.
 4. Themethod of claim 1, wherein the protrusions of the ring element includecurved upper and lower surfaces.
 5. The method of claim 1, wherein thetulip assembly is removable from the fastener.
 6. The method of claim 1,wherein the clamp element comprises a first clamp portion and a secondclamp portion that are separable from one another.
 7. The method ofclaim 6, wherein the first clamp portion and the second clamp portionare press fit into the wedge element to form the clamp element.
 8. Amethod of stabilizing a spine comprising: inserting a fixation systeminto a bone, the fixation system comprising: a fastener including ashaft member and a head member; and a modular tulip assembly capable ofattachment to and removal from the head member of the fastener, fixatinga rod member to the modular tulip assembly.
 9. The method of claim 8,wherein the tulip assembly comprises a polyaxial locking clamp assembly.10. The method of claim 8, wherein the tulip assembly comprises auniplanar locking clamp assembly.
 11. The method of claim 10, whereinthe uniplanar locking clamp assembly comprises a clamp element forreceiving a ring therein.
 12. The method of claim 11, wherein the ringcomprises protrusions for inserting into the clamp element.
 13. Themethod of claim 12, wherein the tulip assembly further comprises a wedgeelement for receiving a rod member therein, wherein the ring withprotrusions is configured to restrict motion between the fastener andmodular tulip assembly along an axis of the rod member.
 14. The methodof claim 8, wherein the modular tulip assembly comprises a wedge elementoperably attached to a clamp element.
 15. The method of claim 8, whereinthe tulip assembly comprises a fracture clamp assembly.
 16. A method ofstabilizing a spine comprising: inserting a fixation system into a bone,the fixation system comprising: a fastener including a shaft member anda head member; a first tulip assembly capable of attachment to the headmember of the fastener, wherein the first tulip assembly comprises apolyaxial tulip assembly; and a second tulip assembly capable ofattachment to the head member of the fastener, wherein the second tulipassembly comprises a uniplanar tulip assembly, fixating a rod member toat least one of the first tulip assembly and the second tulip assembly.17. The method of claim 16, wherein the second tulip assembly comprisesa tulip element, a wedge element, a clamp element and a ring element.18. The method of claim 17, wherein the ring element comprises a pair ofprotrusions for insertion into one or more openings in the clampelement.
 19. The method of claim 17, wherein the wedge element of thesecond tulip assembly comprises a saddle portion configured to receive arod member therein, wherein the ring element restricts the relativemotion between the fastener and an attached second tulip assembly touniplanar motion along an axis of the rod member.
 20. The method ofclaim 17, wherein the wedge element of the second tulip assemblycomprises a saddle portion configured to receive a rod member therein,wherein the ring element restricts the relative motion between thefastener and an attached second tulip assembly to uniplanar motion alongan axis orthogonal to an axis of the rod member.